Counter rod shock absorber



April 28, 1953 Filed March 9. 1950 J. MERCIER COUNTER ROD SHOCK ABSORBER 2 $l-lEETS-SHEET l INVENTOR Jean Merc'z'er Apr-i128, 1953 J. MERCIER 6 COUNTER ROD sHocx ABSORBER 2 SHEETS-S61E81 2 Filed March 9, 1950 INVENTOR Jban Meraaer A: TTEORNEYS Patented Apr. 28, 1953 COUNTER ROD SHOCK ABSORBER Jean Mercier, New York, N. Y.

Application March 9, 1950, Serial No. 148,606 In France January 20, 1950 4 Claims.

The object of the present invention is an improvement in shock absorbers comprising a bellows or telescopic chamber acting as a liquid tank; this improvement being for the purpose of always ensuring a correct filling up of the cy1inder of the shock absorber with liquid (oil, for instance).

This improvement consists essentially in combining with a hollow piston rod bored along its length with spaced apertures a counter-rod, also hollow, associated with the cylinder of the shock absorber and whereon slides the hollow piston rod.

This arrangement enables the liquid from the liquid tank of the shock absorber to supply the lower portion of the cylinder of said shock absorber through the apertures of the hollow piston rod, said hollow piston rod, the hollow counterrod and one or more apertures provided at the lower part of the counter-rod. Figs. 1 and 2 of the appended drawing show in vertical section, by way of non-limitative examples, two types of embodiment of the object of the invention in vertical section.

The shock absorber represented in Figure l is of the type partially described by the applicant, and which was the object of the patent applications for a shock absorber, U. S. Serial Numbers 642,925 and 659,924, now U. S. Patents No. 2,496,952, dated February 7, 1950, and No. 2,565,617, dated August 28, 1951, respectively.

This shock absorber consists of a cylinder I, inside which moves a piston 2, the rod of which 3 goes through the top t of the cylinder and carries at its outside end a disc a bellows 6 is secured, on one hand to said disc 5 and on the other hand to the upper edge of cylinder I.

The bellows 6 (which may be made of leather, rubber or any other equivalent material), the disc 5 and the top 4 limit a flexible chamber A; forming a liquid tank.

The disc 5 and the bottom I of the cylinder are connected respectively at B and 6 to the elements (chassis, and axles of a vehicle, for example, or the like), between which a shock absorbing action is to be obtained.

The piston 2 is drilled with a series of apertures such as It] and II, and comprise alternately a seat !2 on one or the other face of the piston. On these seats I2 may rest two annular flaps I3 and M, which move between said seats and an nular steps I5I6 carried by piston 2.

Each one of the flaps I3--I4 is subjected to the action of a spring i"lI3 which presses: one on the top 4 and the other one on the bottom I of cylinder I.

No tightness packing is provided at the passage of the piston rod 3 through the guiding top 4 of the cylinder; slight leaks which may result from this arrangement return directly to tank A.

The top of cylinder I carries a safety valve consisting, for example, of a ball I9 subjected to the action of a spring 26 and stopping an aperture 2| drilled in the top 4. The purpose of this valve is to limit, in a known manner, to an allowable maximum the stress exerted by the piston 2 when it moves away, while going upwards, from its position of equilibrium, by opening, it will then allow the liquid which is above the piston to flow into the tank A through aperture 2 I.

The piston rod 3 is hollow and slides along a counter-rod 22, also hollow, secured to the bottom "I of the cylinder. Along its length, from place to place, the hollow piston rod 3 is drilled with apertures 23. 6

Finally, an intake valve with a small inertia, comprising preferably a light return spring 24 is arranged at the lower end of the hollow counter-rod 22 and allows the liquid from tank A to flow into the lower portion of cylinder I through an apertur 25.

The operation of the shock absorber is similar to that of the shock absorbers described in the above mentioned patent applications. If the piston 2 moves downwards, the flap l4 closes on the seat I2 of apertures such as It] and is pressed against these seats by the spring I8, while flap I3 opens and allows the free flow through apertures H, from the space under the piston into the space above said piston, of the liquid (oil for instance), which fills cylinder I (and partly the tank A).

During this run of the piston, no damping effect occurs.

During the return stroke of the piston towards its position of equilibrium (represented on the figure), the flap l3 closes and the flap I4 remains closed under the action of the spring I8; thus the liquid cannot flow from the upper portion of the cylinder into the lower portion of the latter, since all apertures III-ll are stopped. In order to flow into said lower portion, the liquid must overcome the action of the spring I8 which, as the piston moves closer to its equilibrium position, is attenuated more and more rapidly.

The result is a damping effect, very strong at first, and then decreasing more and more rapidly.

The same phenomena would take place if the piston were moving in opposite direction from its equilibrium position; the gradually decreasing damping action will then take place when the 3 piston moves back to its equilibrium position and when the liquid tries to flow from the lower into the upper portion of cylinder I against the action of spring ll.

The arrangement of the hollow piston rod 3, drilled with holes, and of the hollow counter rod 22 allows (if the shock absorber is vertical or inclined, the piston rod upwards), the gathering of the air at the upper part of the liquid tank A. The liquid from the latter can, at the same time, feed into the lower portion of cylinder I through the valve 2G; said liquid flowing into the hollow counter rod through apertures 22 of the piston rod, which are masked by the counter rod 22 as the piston 2 moves down into the cylinder.

The exhaust valve l9-2il might also be arranged in the counter rod 22.

If the suspension of the vehicle to be damped, for instance, has a variable flexibility, it will be preferable to provide springs 11-43 with a variable, homothetic elasticity.

There is shown, in Figure 2, a greatly simplified form of embodiment of the invention wherein the shock absorber is of a type comprising no flap or valve, but only apertures of well gauged dimensions.

One finds again, in this figure, the cylinder of the shock absorber, its piston 2 with its hollow rod 3 provided with apertures 22; the hollow counter rod 22 secured to the bottom '5 of cylinder I, and bored at its lower portion with an aperture 25 for the flowing of the liquid (oil for instance). Piston 2 is bored with a gauged port it.

The upper end wall 4 of cylinder 1 is bored with a port 2|.

The liquid tank A is limited by a rubber sheath 26 capable of extension (or a bellows), secured on one hand on the bottom '1 of the cylinder and on the other hand on a disc 5 carried by the upper end of the piston rod 3.

The operation of the shock absorber is easily understood.

The displacements of the piston are damped in both directions by the passage of oil through the gauged port [0, from one of the capacities of the cylinder into the other; and this gauged port opposes rapid oscillations.

The gauged port 2!, which may be omitted, is for the purpose of cooperating in the limitation to an acceptable maximum of the stress exerted by the piston 2 when it moves upwards towards the upper end wall 4, away from its equilibrium position, or when it moves down again, since the lower surface of the piston is larger than its upper surface.

The gathering of the air is effected, as in the previous example of embodiment, at the upper portion of the liquid tank A. And the liquid from said tank: can feed into the lower capacity of cylinder I through the hollow rod 3 and counter rod 22 and their respective ports 23 and 25.

What is claimed is:

1. A shock absorber comprising a substantially cylindrical casing, a wall closing one end of said casing, a plug in the other end of said casing, said plug having an axial bore therethrough, a collapsible chamber afiixed to said casing at the plug end thereof, said chamber having an end wall, a piston slidably mounted in said casing, said piston having an axial bore therethrough, a piston rod aiiixed at one end in the bore of said piston and extending through the bore in said plug into said chamber, said piston rod being aflixed to the end wall of said chamber and having a longitudinal bore therethrough and a plurality of ports therethrough into said longitudinal bore, said piston having a plurality of bores therethrough, said latter bores each having an outstanding rim at one end thereof, at least one of said rims being positioned on each side of said piston, means coacting with said rims, positioned on each side of said piston to close the associated bore in said piston, resilient means normally retaining said closure means on said rims, a hollow counter rod afiixed at one end to the end wall of said casing and extending through said hollow piston rod, a liquid passageway from said casing into said hollow counter rod near the afiixed end thereof, the other end of said hollow counter rod being in communication with said chamber through the ports in said piston rod.

2. The combination set forth in claim 1 in which said collapsible chamber is a bellows.

3. The combination set forth in claim 1 in which said collapsible chamber is a bellows, a passageway is provided through said plug between said bellows and said casing and valve means are provided normally closing said passageway.

4. The combination set forth in claim 1 in which valve means are provided at the afiixed end of said hollow counter rod, normally to close the passageway from said casing into said hollow counter rod.

JEAN MERCIER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,178,996 Duffing Apr. 11, 1915 1,444,248 Hofmann Feb. 6, 1923 2,084,320 Coleman June 22, 1937 2,215,751 Coleman Sept. 24, 1940 2,256,868 Perkins Sept. 23, 1941 2,452,885 Willard Nov. 2, 1948 2,472,840 Lewton June 14, 1949 2,536,626 Coleman Jan. 2, 1951 FOREIGN PATENTS Number Country Date 290,983 Great Britain Nov. 15, 1928 

